Small unmanned aircrafts often use wireless remote controls, and produce lift and change in direction of the aircraft through the forward and reverse rotations of the upper and lower rotors. Compared to large-scaled manned aircrafts, small-scaled aircrafts have the characteristics of having small size, flexibility, low cost, and convenience in landing, so small-scaled aircrafts are widely used in fields such as model aircraft, agriculture, fire prevention and aerial photography. Small-scaled aircrafts usually cannot complete ultra-long flight due to its characteristics such as small size, and light carry load. Therefore, during a flight, if the aircraft experiences a power shortage, it may result in flight shutdown of aircraft, which may very likely lead to a crash. On the other hand, when an operation system of the aircraft experiences a mechanical failure, or an electrical system failure, or an operator error, or an impact from a foreign object (bird strike) or other reasons, it will also cause the remote-controlled aircraft to shut down in flight.
Typically, protective measures taken against the flight shutdown often involve mounting a protection parachute device on the aircraft. The goal is to open the parachute during crash of the aircraft, to realize a slow landing of the aircraft. In prior art, the opening of parachute of a small-scaled aircraft usually involves a user control of a remote controller, and the controller sends out a control command to control the opening of the parachute. Because this mode of control involves a human action to open the parachute, when the aircraft flies at a height outside the view of a human user, a user will fail to determine the flight status of the aircraft and will fail to control the opening of the parachute through the remote controller. When the aircraft is in an abnormal flight state, the failure of timely opening of the parachute will cause a crash and damage to the aircraft.